Wheelchair lifting device

ABSTRACT

A chair lift having a mount, lifting arms supporting a chair platform, and horizontal swivel arms for rotating the chair platform about the mount, a power supply and electrical circuitry being provided for controlling hydraulic pressure in cylinders connected to move the lifting and swivel arms.

0 United States Patent 1 3,638,813 Strong 1 1 Feb. 1, 1972 [54]WHEELCHAIR LIFTING DEVICE 3,458,073 7/1969 Dawson ..214/450 3,476,40411/1969 Rachman.. ....2I4/l A Inventor: J g, 9 10 h Sacra- 3,516,5596/1970 Walter ....214/730 mento, Calif. 95816 lrene Strong, Sacra-3,532,238 10/1970 McMillan ..2l4/67] mento, California, surviving wifeand benificiary under the Last Will and Testament of said John H.Strong, deceased. Primary Examiner-Gerald M. Forlenza AssistantExaminer-John Mannix [22] Attorney-Alexander 8. Blair [21] Appl. N0.:879,651

[ ABSTRACT A chair lift having a mount, lifting arms supporting a chair[52] U.S.Cl ..2l4/148,214/5333; platform, and horizontal Swivel arms forrotating the chair platform about the mount, a power supply andelectrical cir- [51] [Ill-Cl ..B66C 23/00 cuitry being provided forcontrolling hydraulic Pressure in [58] Field of Search ..214/730, 671,660, l A, 148, cylinders connected to move the lifti and Swive] 3mm214/149, 77, DIG. 10

5 Claims, 3 Drawing Figures [56] References Cited UNITED STATES PATENTS2,975,923 3/1961 Ulinski ..214/730 PATENTEBFEB H272 316351813 SHEET 10F3 IN VEN TOR.

4/014 H STRONG BY PATENTEU m H972 3.633.313

1N VEN TOR. Jay/v A. 57k0/V6 A TTORNEY.

INVENTOR.

JOHN H. STRONG BY WHEELCHAIR LIFTING DEVICE This invention relates to aself-operated wheelchair lift. At the present time there is not way fora wheelchair patient, without assistance, to roll his chair out thefront door of his home down the usual three or four steps of the frontstoop of the house, to get from one level to a slightly higher level ofasplit-level home, to board a plane, etc. This invention will alleviatethese problems and when installed will serve many other purposes also.For instance, the device may be installed near a ground floor, kickouttype of emergency window in convalescent homes and hospitals which wouldpermit wheelchair patients to get out of buildings unassisted in theevent of fire or other emergencies. This invention allows the wheelchairpatient to raise, tilt, and rotate the wheelchair in which he is sittingsafely and efficiently in order to get from one place to another withoutaid.

Accordingly, a primary object of this invention is to provide a platformfor safely carrying the wheelchair from one place to another.

Another object of this invention is to provide lifting and horizontalswivel arms which allow the wheelchair to be lifted and rotated to anyposition desired within range ofthe device.

A further object of this invention is to provide a hydraulic pressuresource and electrical circuitry so that the wheelchair patient maycontrol the lifting and horizontal swivel arms by himself without aid.

A still further object of this invention is to provide means for tiltingthe wheelchair platform in order to prevent the wheelchair from rollingoff the platform while being lifted and carried.

The above and other objects of this invention will become apparent tothose skilled in the art after a consideration of the following detaileddescription of the various forms of this invention taken together withthe accompanying drawings, in which:

Flg. l is a plan view of the wheelchair lift illustrating the range ofrotation from inside a building out through a double door;

FIG. 2 is an elevational sectional view taken on line 2-2 of FIG. 1illustrating how the wheelchair is lifted, tilted, and lowered; and

FIG. 3 is a schematic diagram of the electrical control circuitry.

Referring to the drawing in greater detail, there is illustrated inFIGS. 1 and 2 a power unit connected to a mount 12 which is secured tothe floor level by means of a plate 14. Pivotally attached to mount 12are upper and lower horizontal swivel arms 16, 16 which support at theirends a vertical post 18. A lower lifting arm 20 and an upper lifting arm22 are pivotally connected at one end thereof to vertical post 18 andpivotally support at the other end the rear platform post 24 which isvertically secured at the bottom thereof to the rear of the wheelchairplatform 26. Platform 26 has cutouts 28, 28 at the rear and on each sidethereof so that as a wheelchair 30 is rolled backward onto platform 26,the rear wheels 32 will roll into cutout 28 and will rest on the groundor floor being exposed beneath platform 26. Extending outward, as shownin FIG. 2, from a mount on rear platform post 24 are a pair of arms oradjustable chair stops 34 equipped with rubber guards 36 and a seatbelt38.

A hydraulic cylinder 40 is pivotally connected between mount 12 andvertical post 18 with its ram end 42 pivotally attached to vertical post18. FIG 1 illustrated how hydraulic pressure within cylinder 40 pushesout ram 42 thereby causing vertical post 18 to swing about mount 12 fromthe solid line position within a building to the dotted line positionoutside the building where ram 42 is shown extended outward.

A hydraulic lift cylinder 44 is pivotally connected between the bottomof vertical swing post 18 and upper lifting arm 22, its ram end 46 beingattached to upper lifting arm 22. Hydraulic pressure forces ram 46outward from its normal position causing upper lifting arm 22 to liftrear platform post 24 and wheelchair platform 26. At a predeterminedheight above floor level a link stop 48 will prevent further pivotalmovement of lower lifting arm 20 in clockwise direction. At this pointin time, an adjustable spring-operated friction clutch 50 secured torear platform post 24 and upon which upper lifting arm 22 is pivotallyattached, will move from the top of a slot 52 in upper lifting arm 22where it was held by friction toward the bottom of slot 52 as upperlifting arm 22 continues to pivot in the clockwise direction. As upperlifting arm 22 moves upward past friction clutch 52, rear platform post24 will be tilted about the pivot 54 of lower lifting arm 20 which isnow in a fixed position because of link stop 48. As wheelchair platform26 lifts and tilts, rear wheels 32 roll into platform cutouts 28 asshown by reference numeral 32 in FIG. 2 making it impossible for thewheelchair to roll off wheelchair platform 26. The tilt of rear platformpost 24 and the clockwise movement of upper lifting arm 22 areterminated when upper lifting arm 22 makes physical contact withvertical swing post 18 in the position shown in FIG. 2 where upperlifting arm 22 is labeled 22'. When the wheelchair is to be lowered,hydraulic pressure will be withdrawn and applied to the ram end ofcylinder 44 causing ram 46 to be lowered as will be explained later andin more detail. When the wheelchair is to be lowered to a height belowfloor level, hydraulic pressure is withdrawn and applied in the samemanner causing upper and lower lifting arms 22 and 20 respectively topivot in the counterclockwise direction lowering the wheelchair to thelower site, wheelchair platform 26 being lowered until ram 46 iscompletely lowered into hydraulic lift cylinder 44 or until lowerlifting arm 20 makes contact with the edge of the upper level surface atpoint 56.

There is shown in FIG. 3 a reservoir 68, a pump 70, an elevation control72 and a swing control 74. When the wheelchair is to be lifted,elevation control 72 is switched to the "up" contact. Current flows tocontrol solenoid 76 which, upon actuation, opens a hydraulic valve 78allowing pressure to enter hydraulic lift cylinder 44. When elevationcontrol 72 close circuits with the up" contact, current will also passthrough an isolation relay 80 which, upon actuation, close circuitscontacts 82 and 84 sending the current to a 2-second delay vacuum tube86. The current passes through a relay 88 and then actuates an electricmotor control relay 90 to start pump 70 pumping hydraulic oil throughline 92 which is connected to hydraulic valve 78. Control solenoid 76,having opened hydraulic valve 78 to line 92 and line 94, allows thehydraulic oil to pass through line 94 into the bottom of hydraulic liftcylinder 44 forcing ram 46 upward. When elevation control 72 is switchedto the down" contact, current in the same manner as already describedwill pass to control sole noid 76 which will be actuated to open uphydraulic valve 78 to connect line 92 with the line 98. Current alsopasses through isolation relay 96, vacuum tube 86, relay 88, andelectric motor control relay 90 actuating pump 70 to pump hydraulic oilthrough lines 92 and 98 which is connected to the top of hydraulic liftcylinder 44 so that the hydraulic oil forces ram 46 downward. Hydraulicoil pressure below ram 46 is withdrawn at the bottom of hydraulic liftcylinder 44 by means of line 94 and return line 100.

When the wheelchair is to be swung through a door opening, a swingcontrol is switched to the right" contact allowing current to pass to acontrol solenoid 112 which, upon actuation, opens a hydraulic valve 114connecting pressure line 92 with a pressure line 116. Current alsopasses through isolation relay 118, vacuum tube 86, relay 88, andelectric motor control relay 90 actuating pump 70 which pumps hydraulicoil through line 92 and line 116 which is connected at the base ofhydraulic swing cylinder 40 allowing hydraulic oil pressure to push ram42 outward.

A door safety switch 120 connected in series with a tilt safety switch122 prevents any swinging movement at any time except when doors 124 ofFIG. 1 are in the open position and wheelchair platform 26 has beenraised and tilted. Also, there may be another switch (not shown in thedrawing) which automatically activates arms to extend outward from chairstops 34 in front of the wheelchair patient prior to lifting rather thanusing seatbelts 38 which manually have to be adjusted and put on andwhich would probably be neglected by wheelchair patients just as areautomobile seatbelts.

When the wheelchair is to be swung back through doors I24, swing control74 is switched to left" contact allowing current to flow to controlsolenoid l 12 which actuates hydraulic valve 114 to connect line 92 withthe pressure line 126. Current also passes to isolation relay 128,vacuum tube 86, relay 88, and electric motor control relay 90 actuatingpump 70 to pump hydraulic oil pressure through line 92 and line 126which is connected at the front of hydraulic swing cylinder 40 so thathydraulic pressure will push ram 42 back into cylinder 40. Hydraulicpressure is withdrawn from the base of hydraulic swing cylinder 40 bymeans of lines H16 and 100.

It is possible to have a control swing from 45 to 180. A warning buzzer(not shown in the drawing) is actuated when the wheelchair is moving.

The uses of the wheelchair lifting device just described are numerous.For instance, many wheelchair patients are capable of operating motorvehicles with modified controls. This lift makes it possible for theindividual to enter the vehicle, roll up to the drivers location,properly secure his chair, and drive unassisted. This device also inmany cases eliminates hard to negotiate ramps. It gives freedom ofmovement and independence to wheelchair patients and eliminates a greatamount of strain with regard to stairs in private homes.

Probably one of the most important implications of this device would bethe facilitation of transportation of wheelchair patients in buses andsmall vans and also house trailers, recreational vehicles, and mostother mobile vehicles. A switchbox 150 fixedly mounted on the wheelchairplatform or supported by a flexible cable 152, as shown in FIG. 2, isconnected to the control circuitry panel 148 on mount 12 so that thewheelchair patient may operate the device unassisted. Cable 152 may beof any length so that the wheelchair lifting device may be operated fromany position or location necessary for practical use under theparticular circumstances.

While the preferred embodiments of this invention have been illustratedand described, it will be understood by those skilled in the art thatchanges and modifications may be resorted to without departing from thespirit and scope of the invention.

it is claimed:

1. A wheelchair lifting device, comprising:

a mount;

first means pivotally connected to said mount for swinging thereabout;

a wheelchair platform;

second means pivotally connected to said first means and partiallyconnected to said wheelchair platform for lifting and tilting saidwheelchair platform, the tilt being about a horizontal axis;

a power source connected to said amount for activating said first meansand said second means in the alternative;

a control circuit for actuating said power source;

said second means comprising a lower arm pivotally connected betweensaid first means and said wheelchair platform;

an upper arm pivotally connected between said first means and saidwheelchair platform and having a vertical slot at the end adjacent saidwheelchair platform; and

a hydraulic cylinder pivotally connected to said first means at one endthereof and having a ram at the other end thereof pivotally connected tosaid upper arm, said ram, upon being activated by said power source,extending upward from and moving downward into said hydraulic valve, inthe alternative, rotating said upper arm and said lower arm in aclockwise and a counterclockwise direction, in the alternative, abouttheir respective pivot points located at said first means forrespectively raising and lowering said wheelchair platform. 2. Thewheelchair lifting device of claim 1 comprising a horizontal memberextending from said wheelchair platform and protruding through the slotof said upper arm, said upper arm eing pivotally attached to said wheechair platform in a friction fit so that said horizontal member does notfall down to the bottom of the slot of said upper arm from the weight ofsaid wheelchair platform, and a link stop adjacent said lower arm forterminating its upper clockwise movement at a predetermined height, saidupper arm continuing clockwise movement after the termination of theclockwise movement of said lower arm causing said horizontal member toslide down to the bottom of the vertical slot of said upper arm allowingsaid wheelchair platform to pivot about its pivot point adjacent saidlower arm.

3. A wheelchair lifting device, comprising:

a mount;

first means pivotally connected to said mount for swinging thereabout;

a wheelchair platform;

second means pivotally connected to said first means and partiallyconnected to said wheelchair platform for lifting and tilting saidwheelchair platform, the tilt being about a horizontal axis;

a power source connected to said mount for activating said first meansand said second means in the alternative;

21 control circuit for actuating said power source;

said control circuit comprising first switch means;

a control solenoid;

a hydraulic valve connected between said control solenoid and said firstmeans;

delay means;

said power source including a pump and a reservoir; and

pressure lines connected between said reservoir and said hydraulic valveand between said hydraulic valve and said first means, said first switchmeans connected in series with said control solenoid to open saidhydraulic valve and also connected in series with said delay means andthe pump of said power source for pumping oil pressure through saidpressure line by means of the opened hydraulic valve to activate saidfirst means.

4. The wheelchair device of claim 3, comprising second switch meansconnected between said first switch means and a door through which thewheelchair is to be moved, said second switch means connected to a doorand closing circuit when the door is in the open position, and thirdswitch means connected in series between said second switch means andsaid first switch means and closing circuit only after said second meanshas been activated.

5. The wheelchair device of claim 4, wherein said delay means comprisesa plurality of relays and a vacuum tube connected in series between saidfirst switch means and the pump of said power source.

1. A wheelchair lifting device, comprising: a mount; first meanspivotally connected to said mount for swinging thereabout; a wheelchairplatform; second means pivotally connected to said first means andpartially connected to said wheelchair platform for lifting and tiltingsaid wheelchair platform, the tilt being about a horizontal axis; apower source connected to said amount for activating said first meansand said second means in the alternative; a control circuit foractuating said power source; said second means comprising a lower armpivotally connected between said first means and said wheelchairplatform; an upper arm pivotally connected between said first means andsaid wheelchair platform and having a vertical slot at the end adjacentsaid wheelchair platform; and a hydraulic cylinder pivotally connectedto said first means at one end thereof and having a ram at the other endthereof pivotally connected to said upper arm, said ram, upon beingactivated by said power source, extending upward from and movingdownward into said hydraulic valve, in the alternative, rotating saidupper arm and said lower arm in a clockwise and a counterclockwisedirection, in the alternative, about their respective pivot pointslocated at said first means for respectively raising and lowering saidwheelchair platform.
 2. The wheelchair lifting device of claim 1comprising a horizontal member extending from said wheelchair platformand protruding through the slot of said upper arm, said upper arm beingpivotally attached to said wheelchair platform in a friction fit so thatsaid horizontal member does not fall down to the bottom of the slot ofsaid upper arm from the weight of said wheelchair platform, and a linkstop adjacent said lower arm for terminating its upper clockwisemovement at a predetermined height, said upper arm continuing clockwisemovement after the termination of the clockwise movement of said lowerarm causing said horizontal member to slide down to the bottom of thevertical slot of said upper arm allowing said wheelchair platform topivot about its pivot point adjacent said lower arm.
 3. A wheelchairlifting device, comprising: a mount; first means pivotally connected tosaid mount for swinging thereabout; a wheelchair platform; second meanspivotally connected to said first means and partially connected to saidwheelchair platform for lifting and tilting said wheelchair platform,the tilt being about a horizontal axis; a power source connected to saidmount for activating said first means and said second means in thealternative; a control circuit for actuating said power source; saidcontrol circuit comprising first switch means; a control solenoid; ahydraulic valve connected between said control solenoid and said firstmeans; delay means; said power source including a pump and a reservoir;and pressure lines connected between said reservoir and said hydraulicvalve and between said hydraulic valve and said first means, said firstswitch means connected in series with said control solenoid to open saidhydraulic valve and also connected in series with said delay means andthe pump of said power source for pumping oil pressure through saidpressure line by means of the opened hydraulic valve to activate saidfirst means.
 4. The wheelchair device of claim 3, comprising secondswitch means connected between said first switch means and a doorthrough which the wheelchair is to be moved, said second switch meansconnected to a door and closing circuit when the door is in the openposition, and third switch means connected in series between said secondswitch means and said first switch means and closing circuit only aftersaid second means has been activated.
 5. The wheelchair device of claim4, wherein said delay means comprises a plurality of relays and a vacuumtube connected in series between said first switch means and the pump ofsaid power source.